Hydraulic counterweight for boat elevator

ABSTRACT

A hydraulic counterweight device for a boat elevator of the &#39;&#39;&#39;&#39;water-slope&#39;&#39;&#39;&#39; type which comprises a navigation and an auxiliary channel disposed between an upstream and a downstream pool. In both channels a mass of water is retained by a movable gate which is pushed up or pulled down the channel by a carriage movable on the banks of the channel, the two carriages being interconnected by cables. The invention provides that the auxiliary channel which is not used to transport boats, has a length substantially equal to that of the navigation channel and a slope which is less than or equal to that of the navigation channel, so that the downstream end of the auxiliary channel is located at a level which is higher than or the same as the level of the downstream pool.

United States Patent Aubert [151 3,656,305 Apr. 18,1972

[54] HYDRAULIC COUNTERWEIGHT FOR BOAT ELEVATOR [2]] Appl. No.: 116,338

FOREIGN PATENTS OR APPLICATIONS 1,411,084 8/1965 France ..61/8 1,583,405 9/1969 France ..61/9

Primary ExaminerJacob Shaprio Att0rneyYoung & Thompson [57] ABSTRACT A hydraulic counterweight device for a boat elevator of the water-slope type which comprises a navigation and an auxiliary channel disposed between an upstream and a downstream pool. In both channels a mass of water is retained by a movable gate which is pushed up or pulled down the channel by a carriage movable on the banks of the channel, the two carriages being interconnected by cables. The invention provides that the auxiliary channel which is not used to transport boats, has a length substantially equal to that of the navigation channel and a slope which is less than or equal to that of the navigation channel, so that the downstream end of the auxiliary channel is located at a level which is higher than or the same as the level of the downstream pool.

16 Claims, 18 Drawing Figures PATENTED PR 18 1912 3,656,305

SHEET 1 UF 6 JEAN 40.5527

PATENTEDAPR 18 I912 3.656.305

' sum 3 [IF 6 PATENTEIJ APR 18 1972 SHEET 5 BF 6 AWE/rm? die/v flua er HYDRAULIC COUNTERWEIGHT FOR BOAT ELEVATOR This invention relates to a hydraulic counterweight device for a boat elevator of the water-slope type.

A water-slope elevator" is usually understood to refer to a system comprising a navigation channel which is inclined to the horizontal plane and located between an upstream pool and a downstream pool. A mass of water which will be designated hereinafter as a "water triangle" and on which a boat is intended to float isretained within said channel by a movable barrier or gate which is supported by a carriage on the top edges of the channel side-walls. The supporting carriage can be equipped with drive units which are capable of displacing the movable retaining gate and the carriage either in one direction or in the other along the channel.

In order to reduce the cost price and the weight of the supporting carriage, it has been proposed to make use of hydraulic counterweight systems of the type comprising an auxiliary channel which is adjacent to the navigation channel and located between said upstream and downstream pools, a balancing mass of water retained within said auxiliary channel by means of an auxiliary movable gate which is supported by a carriage on the sidewall edges of said channel and flexible coupling means such as cables for interconnecting the carriages which support the main and auxiliary movable retaining-gates.

In these known systems, the auxiliary channel is also intended to be used for navigation whilst the water triangles of both channels can be identical and can each transport one boat simultaneously in the downward or upward direction respectively, thus serving as counterweights for each other.

This simultaneous use of both channels for navigation purposes makes it necessary to provide special installations for each channel.

In fact, the downstream end of the two channels must be located at a level either equal to or lower than that of the bottom of the downstream pool in order to permit the passage of boats. When one water triangle has come close to the upstream end of a channel, the other water triangle is located near the downstream end of the other channel. In order that the counterweight action should still be exerted in this position, it is necessary to ensure that the downstream face of the retaining-gate which is located at the downstream end is not subjected to water pressure. It is therefore necessary to separate the downstream endsof the two channels from the downstream poolby means of a rocking tail-gate.

When said gate is lowered so as to transfer the boat into the downstream pool, the counterweight action is cancelled. In consequence, provision has to be made at the downstream end of the channels for latches which serve to prevent the water triangle in the upstream position from moving backwards.

Finally, in order to start the movement in the opposite direction when the downstream pool gate has been raised, the water which is present between said gate and the retaininggate which is located in the downstream position must be discharged in order that the counterweight action should again be exerted. In the known systems, provision was accordingly made in the floor of each channel and in proximity to the downstream pool for a cavity fitted with sluice-gates into which the water referred-to above is discharged. It is clearly also necessary to provide a pumping system which subsequently delivers the water from the cavity into the downstream pool.

The capital expenditure involved in these installations can be difficult to amortize if the traffic is not very heavy.

The mainobject of this invention is to simplify the equipment at the channel ends in the event that only one of the two channels is sufficient to handle boat traffic whilst the auxiliary channel is used solely for the operation of the hydraulic counterweight.

In accordance with the invention, the hydraulic counterweight device of the type specified in the foregoing is characterized in that the auxiliary channel has a length which is substantially equal to that of the navigation channel and a gradient which is equal at a maximum to the gradient of the navigation channel, the upstream end of the auxiliary channel being located substantially at the level of the upstream pool and the downstream end of said channel being consequently located at a level which is at least equal to the level of the downstream pool.

Under these conditions, the rocking-type tail-gates which form a separation between the downstream pool and the downstream end of each of the two channels are no longer necessary. It is also possible to dispense with the discharge cavities together with their pumping and sluice'gate system.

In a preferred embodiment, the counterweight device comprises a stationary valve system for transferring water from the upstream pool into the balancing water-mass and a valve system attached to the auxiliary retaining-gate in order to discharge the water from said balancing mass into the downstream pool.

It is thus possible to vary the balancing mass at will as a function of its position in the auxiliary channel and to regulate the motion of a boat within the navigation channel without having recourse to any motive power other than that of the water.

In an advantageous embodiment, the auxiliary retaininggate is constituted by a segmental gate, the corresponding supporting carriage being provided with means for lifting said gate with respect to the floor of the auxiliary channel.

Provision is thus made for a simple arrangement in which the movable valve system serves to discharge the water of the balancing mass into the downstream pool- In an advantageous embodiment, the device further comprises a stationary valve system for transferring thewater from the upstream pool into the water triangle of the navigation channel and for a valve system which is attached to the main movable retaining-gate in order to discharge the water of said triangle into the downstream pool.

At the end of the downward travel of a boat within the navigation channel, the main movable: retaining-gate can thus be moved forward in spite of the resistance set up by the water of the downstream pool and the boat can then be transferred into said pool without any motive power other than that of the water as will be described hereinafter.

In a preferred embodiment, the main movable retaininggate is constituted by a segmental-gate and the corresponding supporting carriage comprises means for lifting said gate in order to permit the water of the water triangle to pass from the navigation channel into the downstream pool.

Further important properties of the invention will become apparent from the following description, a number of embodiments of the invention being illustrated in the accompanying drawings which are given by way of example without any implied limitation, and in which:

FIG. 1 is a diagrammatic view in elevation of a navigation channel;

FIG. 2 is a diagrammatic view in elevation of the auxiliary channel;

FIG. 3 is a diagrammatic plan view of the channels of FIG. 1 and 2;

FIGS. 4 to 12 are diagrams representing the different stages of upward and downward transfer of a boat;

FIG. 13 is a diagrammatic plan view of an alternative embodiment of the hydraulic counterweight device;

FIG. 14 is a diagrammatic vertical sectional view of an auxiliary movable retaining-gate and its supporting carriage;

FIG. 15 is the plan view which corresponds to FIG. 14;

FIG. 16 is a part-sectional plan view of the system of attachment of the connecting cables between supporting carriages;

FIG. 17 is a partial view in perspective with portions broken away and showing the system adopted for passing the cables beneath the channels;

FIG. 18 is a diagrammatic vertical sectional view of a main retaining-gate and its supporting carriage.

There are shown diagrammatically in FIGS. 1 to 3 a waterslope elevator with hydraulic counterweight comprising a navigation channel 101 and an auxiliary channel 102 which is not employed for effecting the transfer of boats. Said channels 101 and 102 are adjacent to each other and located between an upstream pool 103 and a downstream pool 104 representing, for example, the upper and lower reaches of a waterway which is obstructed by a dam 105 (as shown in FIG. 3).

The upstream end of the navigation channel 101 is located at the level of the upstream pool 103 and is separated from this latter by a rocking head-gate 106. The downstream end of said navigation channel 101 is located at a lower level than that of the downstream pool 104 and connects with said pool without interposition of any gate.

The upstream end of the auxiliary channel 102 is also located at the level of the upstream pool 103 and is separated from this latter by a stationary wall 107. The two channels 101 and 102 have substantially the same length but the gradient of the auxiliary channel 102 is of smaller value than or at the most equal to the gradient of the navigation channel 101, with the result that the downstream end of the auxiliary channel is located at a level which is either higher than or at least equal to the level of the water in the downstream pool 104. These indications will be given in greater detail hereinafter.

A main retaining-gate 108 supported by a carriage 109 is capable of moving within the navigation channel 101 between a bottom position 1080 and a top position 108b. The carriage 109 is supported by its wheels on the two top edges of the channel 101. The gate 108 is intended to retain a water triangle 111 on which a boat 112 is carried. A fixed valve system which is represented in the figures by a cock 113 solely for the sake of illustration and mounted in the rocking gate 106 serves to transfer the water from the upstream pool 103 to the water triangle 111. A second valve system which is attached to the main retaining-gate 108 and represented diagrammatically by a cock 114 serves to discharge the water of the water triangle 111 towards the downstream pool 104.

An auxiliary retaining-gate 115 supported by a carriage 116 is movable within the auxiliary channel 102 between a bottom position 115a and a top position 115b. The distance between these two positions as measured along the channel is equal to the distance between the top position 10811 and the bottom position 103a of the main retaining-gate 108. Moreover, the gradient of the auxiliary channel is such that the base of the auxiliary retaining-gate in the bottom position 115a is located at a level which is either equal to or higher than that of the water in the downstream pool 104.

The auxiliary gate 115 retains a balancing water-mass 117. A fixed valve system represented diagrammatically by a cock 118 extends through the wall 107 and serves to transfer water from the upstream pool 103 into the mass 117. A second valve system which is attached to the auxiliary movable retaininggate 115 and represented diagrammatically by a cock 119 serves to discharge the water of the mass 117 towards the downstream pool 104.

In order to ensure a counterweight action, the maximum balancing mass 117 must be greater than that of the water triangle 111 in order to compensate for the lower gradient of the auxiliary channel 102. To this end, the height of the auxiliary retaining-gate 115 is higher than that of the main retaininggate 108 or alternatively the width of the auxiliary channel 102 is greater than that of the navigation channel 101.

The supporting carriages 109 and 116 are connected to each other by means of two sheets of cables. An inner sheet 122 follows the adjacent top edges of the channels 101 and 102 and extends from the top edge of one channel to the top edge of the other channel over pulleys 123 which have vertical shafts and are securely anchored to the ground (FIG. 3). An outer sheet of cables 124 extends along the opposite top edges of the two channels and across these latter. The cables can be passed across the channels and above these latter either by means of sets of pulleys 125, 126 having horizontal shafts at right angles to each other as shown in FIGS. 1 and 2 or by means of a gantry. The passage of cables across the channels can also be effected underground (as shown in FIGS. 3 and 17 as will be explained hereinafter.

Referring now to FIGS. 4 to 12, the transfer of boats is carried out as follows:

When a boat is to be elevated from the downstream pool 104 to the upstream pool 103, the main retaining-gate 108 is raised from the bottom position 108a in order to transfer the boat to the water triangle 111 and the main retaining-gate is then lowered in order to separate the water triangle from the downstream pool 104 (as shown in FIG. 4). At this moment, the auxiliary retaining-gate is in the top position 115b and the balancing mass 117 is reduced to a minimum value which is calculated so as to maintain the cables 122, 124 in tension concurrently with the weight of the main retaining-gate.

In order to impart initial acceleration to the water triangle 111 (shown in FIG. 5) the fixed valve system 118 is opened in order to increase the volume of the balancing mass 117. During this initial stage, equal and opposite thrust forces are applied to the main retaining-gate 1080 by the water triangle 111 and the downstream pool 104, with the result that only a small balancing mass is necessary to initiate the motion of the main retaining-gate.

As the main gate 108 moves upwards, the thrust exerted by the water of the downstream pool 104 becomes progressively lower and is reduced to zero when the downstream face of the main retaining-gate is entirely dry (as shown in FIG. 6). The valve system 118 is again opened in order to bring the balancing mass 117 to its maximum value and to obtain the desired acceleration of the main retaining-gate 108.

When the main gate has reached its normal rate of upward motion (FIG. 7), the movable valve system 119 which is attached to the auxiliary retaining-gate is opened and part of the water of the balancing mass 117 is discharged into the downstream pool 104. The balancing mass is thus brought to its normal value in order that the weight component of said mass which is tangential to the channel 102 should balance the weight component of the water triangle 111 which is tangential to the channel 101 as increased by the friction forces applied by the cables to their pulleys and by the residual tension of the cables. The total acceleration of the moving system is then zero and normal motion at constant speed is then obtained.

When the main retaining-gate comes close to the top position 108b (as shown in FIG. 8), the movable valve system 119 is again opened in order to reduce the balancing mass still further and to slow-down the system.

After reaching the position 108b, the main retaining-gate is locked in position by the brakes of its supporting carriage 109. The boat is transferred into the upper pool 103 and passes over the gate 106 which has been lowered to the horizontal position under the pressure exerted by the water triangle 111 on the downstream face of said gate when the level of said triangle reaches the level of the upstream pool 103. Another boat comes into position on the water triangle in order to move downwards towards the lower pool 104. As soon as the brakes of the supporting carriage 109 are released, the downward motion begins with moderate acceleration by reason of the fact that, as has just been stated, the balancing mass 117 has been reduced at the end of the previous upward transfer.

Under the effect of said acceleration, the rate of downward motion of the main retaining-gate 108 increases and when it has attained the desired operating speed (FIG. 9), the stationary valve system 118 is opened in order to increase the balancing mass 117 and to reduce the total acceleration of the moving system to zero. The downward motion accordingly continues at constant speed.

When the main retaining-gate 108 comes close to its bottom position 108a (as shown in FIG. 10), the water of the downstream pool applies to the downstream face of said gate a thrust which progressively increases in value and which tends to slow-down the downward motion. In order that this motion should continue, the movable valve system 119 which is attached to the auxiliary retaining-gate is opened and practically the entire quantity of the water of the balancing mass 117 is discharged into the downstream pool 104.

As the main retaining-gate 108 continues to move downwards, a back-pressure is applied to said gate by the water of the downstream pool 104 and becomes progressively higher. Although the balancing mass is fully emptied at this moment, said back-pressure which is added to the friction forces and to the residual tension of the cables would prevent continuation of the movement until the normal stopping position is reached.

In order to overcome this back-pressure, it is possible either to weight the main retaining-gate or to place a drive unit on its supporting carriage 109. A preferred solution which is illustrated in FIGS. 11 and 12 consists in opening the stationary valve system 113 in order to pass an additional mass of water from the upstream pool 103 into the water triangle 111. The level 127 within the triangle 111 is then higher than that of the downstream pool 104 (as shown in FIG. 11), so that a total thrust is exerted on the retaining-gate 108 in the downward direction and is sufficient to overcome friction forces and the tension of the cables. The end of the downward motion takes place at a progressively lower speed.

The main retaining-gate having accordingly reached the bottom position 108a (as shown in FIG. 12), the supporting carriage 109 is secured in position by means of its brakes and the movable valve system 114 which is attached to the main gate is opened so as to bring the level of the water triangle which was located at 127 to the same level as the downstream pool. The retaining-gate 108 can then be lifted in order to pass the boat into the downstream pool. The system has returned to the state shown in FIG. 4 and is in readiness for the upward transfer of another boat.

In the alternative embodiment which is illustrated in FIG. 13, provision has been made for additional arrangements whereby withdrawals of water which are carried out during transfer of boats within the navigation channel are prevented from rapidly producing adverse effects on the upstream pool.

The rocking gate 106 which separates the upstream pool 103 from the navigation channel 101 is not provided with any valve system in this form of construction. A diversion channel 131 of small cross-section is provided between the upstream pool and the navigation channel and the stationary valve unit 113 is placed across said channel.

Furthermore, a compensation basin 132 is provided between the upstream pool 103 and the auxiliary channel 102. Said basin 132 communicates with the upstream pool 103 via a throat 130, a grid 134 being placed upstream of said throat in order to prevent floating debris from passing through this latter.

When the valve system 118 is opened, the water which is necessary to increase the balancing mass is supplied by the basin 132. Even if a substantial quantity of water is withdrawn at a high rate, the throat 130 prevents the water of the upstream pool 103 from flowing at a high velocity. The basin 132 fills slowly between the withdrawals through the throat 130.

A similar basin can be arranged in the downstream portion in order to prevent disturbances of the downstream pool as a result of discharge of the balancing mass of water.

The movable valve system 119 which is attached to the auxiliary retaining-gate 115 can be constructed in a simple manner if the auxiliary gate is constituted by a segmental gate as shown in FIGS. 14 and 15. It is known that a gate of this type comprises a leaf 133 constituted by a portion of a cylinder of revolution and disposed transversely with respect to the channel 102 and two vertical side-plates 134 which are parallel to the sidewalls of the channel. The ends of the sideplates 134 are pivoted about a pin 135 which is attached to the supporting carriage 116 at the upstream end of this latter, the leaf 133 being located at the downstream end of the carriage. The axis of symmetry of the leaf 133 coincides with the pivotal axis or pin 135.

The supporting carriage 116 is made up of two frames 136 which are carried by four wheels respectively on the two top edges of the channel. The frames 136 are connected together by means of cross-members 137 and a brace 138 in the form of a cross. The frames 136 are adapted to carry a winch 139 at the downstream end, there being wound onto said winch a cable 141 which passes over a pulley 142 and the end of which is attached to the leaf 133.

Inasmuch as the downstream face of the retaining-gate 133 is continuously in the dry state, said gate is subjected only to the pressures which are exerted by the balancing mass 117. By reason of the geometry of the retaining-gate, the resultant of said pressures passes continuously through the pivotal axis 135.

The length of the side-plates 134 is chosen so that, when the mass of water 117 has reached the maximum level, said resultant traverses the supporting plane of the carriage as defined by the points of contact of the wheels with the ground at a point 0 which is located at equal distance from the upstream and downstream axles of the carriage 116. When the level of the mass 117 falls, the resultant of the pressures changes to a slight extent but again traverses the supporting plane at a point located within the axles of the carriage. Thus. the forces exerted on the carriage 1.16 by the retaining-gate 133 continuously tend to apply said carriage against the ground. Since said carriage does. not support any drive mechanism and does not require to be weighted for the reasons given above, said carriage can be of lightweight and inexpensive construction.

The side-plates 134 are intended to have a small thickness in order to offer a certain degree of flexibility, thereby permitting the leaf 133 to remain centered within the channel even if the carriage 116 were to assume a slightly sloping position.

Discharge of the water of the mass 117 towards the downstream pool is carried out simply by lifting the retaininggate 133 by means of the winches 139.

The sheets of connecting cables 122 and 124 can be coupled to the supporting carriages by means of compensatingbars. It has been assumed in the drawings that each sheet consisted of four cables. Said cables are distributed in two pairs, each pair being attached to one compensating-bar 143. Each bar 143 is in turn attached to another bar 144 which is attached to one of the frames 136 by means of a swivel-bearing.

In addition to said compensating system or instead of this latter, provision can be made as shown in FIG. 16 for hydraulic jacks 145, the piston of each jack being connected to one of the cables of the sheet and the jack body being connected to the compensating-bars 143 as illustrated or directly to the frame 136. The oil-filled chambers 146 of said jacks are connected by means of pipes 147 to a common storage tank 148. The tensions of the four cables are thus maintained equal to each other even if the cables stretch to an unequal extent. If a cable stretches to an excessive degree, it will clearly be necessary to adjust its length before the corresponding piston reaches the end of its travel.

The sheets of cables 122 and 124 are supported by sets of paired pulleys which are distributed along the top edges of the two channels. As has been stated earlier, the outer sheet 124 can pass either above or beneath the two channels. A cable passage beneath the channels is shown in FIG. 17. The device comprises two vertical wells 151 which are connected to each other by an underground duct 152 which extends beneath the two channels. The cables are guided by pulleys 153 which are located at the surface and pulleys 154 which are placed at the bottom of the wells 151, the shafts of the pulleys 153 and 154 being horizontal and at right angles to each other. It will be noted that the tension of the cables tends to apply the pulleys 153 against the ground, with the result that the pulley shafts can be anchored at lower cost than in the case of a cablepassage by means of a gantry which is placed above the channels.

Referring now to FIG. 18, improvements to the equipment of the navigation channel will now be described.

The main retaining-gate is constituted by a segmental gate of the type described above in the case of the auxiliary retaining-gate and comprises a cylindrical leaf 155 and two vertical side-plates 156. The side-plates are pivoted about a pin 157 which is attached to the supporting carriage 109 at the upstream end, the cylindrical leaf 155 being located at the downstream end of the carriage.

In a manner which is similar to the supporting carriage of the auxiliary retaining-gate hereinabove described, the carriage 109 consists of two frames 158 which are applied respectively against the two top edges of the navigation channel 101 and connected together by means of an upstream cross-beam 159, a downstream cross-beam 161 and a cross-brace. The pivot-pin 157 of the retaining-gate is carried by the upstream cross-beam 159.

The downstream cross-beam 161 supports by means of a universal joint two hydraulic jacks 162 of the telescopic type, for example, in which the jack piston is attached by means of a universal joint to a cross-member 163 which connects the side-plates 156 of the retaining-gate to each other.

In addition, a stop beam 164 is placed transversely with respect to the channel between the side-plates 156 and upstream of the cross-member 163. Said stop beam 164 is supported by two vertical side-plates 165 and these latter are pivoted about a pin 166 which is carried by the upstream cross-member 159 of the carriage. By means of a universal joint, the downstream cross-member 161 of the carriage supports two hydraulic jacks 167 of the telescopic type, for example, the jack pistons being connected by means of a universal joint respectively to each side-plate 165 of the stop beam. Said jacks comprise dash-pot damping devices.

The structure as thus defined is particularly advantageous when a downwardly moving boat comes close to the downstream pool. As has been stated earlier, the level of the water triangle 111 is intended to be raised in order to overcome the back-pressure which is exerted by the water of the downstream pool.

When the retaining-gate 155 reaches its lowermost position, the brakes of the carriage 109 are applied and the stop beam 164 which is supported by the pressure of the two jacks 167 absorbs the kinetic energy of the boat and thus prevents this latter from colliding with the retaining-gate 155. Said beam 164 also serves to moor the boat in the central portion of the channel.

Once the boat has been secured in position, the jacks 162 are actuated so as to lift the leaf 155, to discharge part of the water of the triangle 111 and to equalize the levels of said triangle and of the downstream pool.

By means of the jacks 162 and 167, the beam 164 and the leaf 155 are then raised and return to their top positions 164a and 155a. The boat moves forward into the downstream pool and is replaced by a boat which is to be transferred in the upward direction.

It is apparent that the incorporation of the stop beam 164 makes it possible to place the segmental gate 155 downstream of the supporting carriage without any attendant danger of impacts. As has been stated in the foregoing in connection with the auxiliary retaining-gate, the resultant of the forces exerted on the carriage 109 by the leaf 155 applies said carriage against the ground, with the result that the carriage does not require to be weighted and can be of lightweight and inexpensive construction. In addition, the water pressure tends to lift the leaf but the weight of this latter and the action of the jacks 162 forestall this tendency.

The retaining-gate or leaf 155 and the side-plates 156 are protected against collisions with boats and can therefore be of small thickness. Moreover, any possible impact caused by a boat as this latter strikes the beam 164 is absorbed by the jacks 167-which accordingly operate as dash-pots and permit the movement of withdrawal of the beam, thus removing any risk of damage.

On the other hand, the volume of the water triangle must be increased by a fraction corresponding to the space formed between the beam 164 and the leaf 155. The resultant increase in tension of the cables is permissible and does not give rise to excessive supplemental expenditure in a balanced water-slope system in accordance with the invention.

As will be readily understood, the invention is not limited to the embodiments which have just been described and many changes could be made in the latter without thereby departing either from the scope or the spirit of this invention.

What I claim is:

1. A hydraulic counterweight device for a boat elevator of the water-slope type comprising an inclined navigation channel disposed between an upstream pool and a downstream pool and a water triangle retained by a main gate which is movable within said channel and supported by a carriage on the top edges of the channel, the counterweight device being such as to comprise an auxiliary channel which is adjacent to the navigation channel and located between said upstream and downstream pools, a balancing mass of water retained by an auxiliary gate which is movable in said auxiliary channel and supported by a carriage on the top edges of said auxiliary channel, and flexible coupling means such as cables for interconnecting the carriages which support the main and auxiliary movable retaining-gates, wherein the auxiliary channel has a length which is substantially equal to that of the navigation channel and a gradient which is equal at a maximum to the gradient of the navigation channel, the upstream end of said auxiliary channel being located substantially at the level of the upstream pool and the downstream end of said channel being consequently located at a level which is at least equal to the level of the downstream pool.

2. A device according to claim 1, wherein said device comprises a stationary valve system for transferring water from the upstream pool into the balancing water-mass of the auxiliary channel and a valve system attached to the auxiliary retaininggate in order to discharge the water from said balancing mass into the downstream pool.

3. A device according to claim 2, wherein the auxiliary retaining-gate is constituted by a segmental gate comprising a cylindrical leaf of revolution placed transversely within the auxiliary channel and two vertical side-plates placed parallel to the sidewalls of said channel and pivoted about a pin, said pin being attached to the carriage which supports the auxiliary retaining-gate.

4. A device according to claim 3, wherein the axis of symmetry of the cylindrical leaf of the auxiliary retaining-gate coincides with the pivot-pin aforesaid.

5. A device according to claim 3, wherein the pivotal axis of the auxiliary retaining-gate is located upstream with respect to the cylindrical leaf of said gate.

6. A device according to claim 3, wherein the carriage which supports the auxiliary retaining-gate comprises means for lifting the cylindrical leaf of said gate with respect to the floor of the auxiliary channel.

7. A device according to claim 1, wherein the devices for interconnecting the two supporting carriages comprise at least one sheet of cables which are connected to the carriages in pairs by means of articulated compensating-bars.

8. A device according to claim 1, wherein the devices for interconnecting the two supporting carriages comprise at least one sheet of cables, each cable of the sheet being connected to the carriages by means of a hydraulic jack and the jack chambers which are filled with fluid being connected to a common balancing storage-tank.

9. A device according to claim 1, wherein said device comprises an underground duct which is formed beneath the navigation channel and the auxiliary channel in the vicinity of the upstream pool and through which are passed the cables for interconnecting the two supporting carriages.

10. A device according to claim 2, wherein said device comprises a compensation basin which connects on the one hand with the upstream pool by means of a throat and on the other hand with the auxiliary channel by means of the stationary valve system aforesaid.

11. A device according to claim 1, wherein said device comprises a stationary valve system for transferring water from the upstream pool into the water triangle of the navigation channel and a valve system attached to the main movable retaining-gate in order to discharge the water of the water triangle into the downstream pool.

12. A device according to claim 11, wherein the main movable retaining-gate is constituted by a segmental gate pivoted about a pin which is attached to the supporting carriage and located upstream with respect to the leaf of said gate.

13. A device according to claim 12, wherein the carriage which supports the main movable retaining-gate comprises means for lifting the leaf of said gate with respect to the floor of the navigation channel.

14. A device according to claim 13, wherein the means aforesaid comprise hydraulic jacks, the piston of each jack being connected to the segmental gate and the jack body being pivoted about universal bearings which are secured to the supporting carriage.

15. A device according to claim 13, wherein said device comprises a stop beam placed transversely with respect to the navigation channel upstream of the leaf of the retaining-gate, said beam being pivoted about a pin and said pin being attached to the carriage which supports the main movable retaining-gate and said carriage being provided with articulated hydraulic jacks adapted to lift the beam and to maintain said beam within the channel.

16. A device according to claim 15, wherein the hydraulic jacks aforesaid comprise damping devices of the dash-pot" type which permit withdrawal of the stop beam under the effect of an impact. 

1. A hydraulic counterweight device for a boat elevator of the water-slope type comprising an inclined navigation channel disposed between an upstream pool and a downstream pool and a water triangle retained by a main gate which is movable within said channel and supported by a carriage on the top edges of the channel, the counterweight device being such as to comprise an auxiliary channel which is adjacent to the navigation channel and located between said upstream and downstream pools, a balancing mass of water retained by an auxiliary gate which is movable in said auxiliary channel and supported by a carriage on the top edges of said auxiliary channel, and flexible coupling means such as cables for interconnecting the carriages which support the main and auxiliary movable retaining-gates, wherein the auxiliary channel has a length which is substantially equal to that of the navigation channel and a gradient which is equal at a maximum to the gradient of the navigation channel, the upstream end of said auxiliary channel being located substantially at the level of the upstream pool and the downstream end of said channel being consequently located at a level which is at least equal to the level of the downstream pool.
 2. A device according to Claim 1, wherein said device comprises a stationary valve system for transferring water from the upstream pool into the balancing water-mass of the auxiliary channel and a valve system attached to the auxiliary retaining-gate in order to discharge the water from said balancing mass into the downstream pool.
 3. A device according to claim 2, wherein the auxiliary retaining-gate is constituted by a segmental gate comprising a cylindrical leaf of revolution placed transversely within the auxiliary channel and two vertical side-plates placed parallel to the sidewalls of said channel and pivoted about a pin, said pin being attached to the carriage which supports the auxiliary retaining-gate.
 4. A device according to claim 3, wherein the axis of symmetry of the cylindrical leaf of the auxiliary retaining-gate coincides with the pivot-pin aforesaid.
 5. A device according to claim 3, wherein the pivotal axis of the auxiliary retaining-gate is located upstream with respect to the cylindrical leaf of said gate.
 6. A device according to claim 3, wherein the carriage which supports the auxiliary retaining-gate comprises means for lifting the cylindrical leaf of said gate with respect to the floor of the auxiliary channel.
 7. A device according to claim 1, wherein the devices for interconnecting the two supporting carriages comprise at least one sheet of cables which are connected to the carriages in pairs by means of articulated compensating-bars.
 8. A device according to claim 1, wherein the devices for interconnecting the two supporting carriages comprise at least one sheet of cables, each cable of the sheet being connected to the carriages by means of a hydraulic jack and the jack chambers which are filled with fluid being connected to a common balancing storage-tank.
 9. A device according to claim 1, wherein said device comprises an underground duct which is formed beneath the navigation channel and the auxiliary channel in the vicinity of the upstream pool and through which are passed the cables for interconnecting the two supporting carriages.
 10. A device according to claim 2, wherein said device comprises a compensation basin which connects on the one hand with the upstream pool by means of a throat and on the other hand with the auxiliary channel by means of the stationary valve system aforesaid.
 11. A device according to claim 1, wherein said device comprises a stationary valve system for transferring water from the upstream pool into the water triangle of the navigation channel and a valve system attached to the main movable retaining-gate in order to discharge the water of the water triangle into the downstream pool.
 12. A device according to claim 11, wherein the main movable retaining-gate is constituted by a segmental gate pivoted about a pin which is attached to the supporting carriage and located upstream with respect to the leaf of said gate.
 13. A device according to claim 12, wherein the carriage which supports the main movable retaining-gate comprises means for lifting the leaf of said gate with respect to the floor of the navigation channel.
 14. A device according to claim 13, wherein the means aforesaid comprise hydraulic jacks, the piston of each jack being connected to the segmental gate and the jack body being pivoted about universal bearings which are secured to the supporting carriage.
 15. A device according to claim 13, wherein said device comprises a stop beam placed transversely with respect to the navigation channel upstream of the leaf of the retaining-gate, said beam being pivoted about a pin and said pin being attached to the carriage which supports the main movable retaining-gate and said carriage being provided with articulated hydraulic jacks adapted to lift the beam and to maintain said beam within the channel.
 16. A device according to claim 15, wherein the hydraulic jacks aforesaid comprise damping devices of the ''''dash-pot'''' type which permit withdrawal of the stop beam under the effect of an impacT. 